Lock-out system for party-line telephones.



No. 833,298. lPATENTED OCT,16, 1906.

W. M. BRUCE, JR..

LOCK-OUT SYSTEM FOR PARTY LINE TELEPHONES. APPLICATION FILED 00MB, 1905.

UNITED STATES PATENT OEEICE;l

WILLIAM M; BRUCE, JE., OE SPRINGFIELD, OH1O,ASSIGNOEEY DIRECT AND MESNE AssIeNMENrs, To TEEL SELECT- TELEPHONE MANUFAC- TUBING COMPANY, OE SPRINGFIELD, OHIO, A CORPORATION or OHIO,

Specification of Letters Patent.

Patented oct. 1e, 190e.

Application filed October 23,1905. ASerial No. 283,921.

To all. whom, `t maypo'ncern:

vBe it known that I,WILLIAM M. BRUCE,

Jr., a citizen of the United States, residing at ling is a specification.

Springfield, 'in the county of Clark and State of Ohio', have invented certain new and usee ful Improvements Lock-Out Systems for PartyLine Telephonespof which the follow- My invention relates to improvements in lopk-outsfor party-line telephones. The object of the inventionis to pro'vide novel means in a common-battery system whereby'when one subscriber of a party-line i putsthe line in use by taking ldown his receiver the other subscribers on the line' are automaticallylocked out.

represents a A further obj ect of the invention is to proyide novel means by which a subscriber -on 'a party-line may, if he desires, communicate with other subscribersfon the same line or permit another subscriber onthe line to come into-the linein` common with the first subscriber. y v f I attain these objects by the'construction shown in the accompanying drawing, which diagrammatic view showing three subscribers stations and the subscribers connection at the central station.

' In the said drawing, a and b'represeynt the opposite sides of the main line, to which any suitable number of subscribers stations may. be connectedV in thegusual way. Blrepresents the commonfbattery at the central .station, which is grounded onone side, as shown at G. The terminals orf-thellne ,a l) 'are-Acon-v nected in the usualwayftofa.s\iitch,"prefeI-' ablyv 'of the ordinary spring-jaclctype. I\ have shown the battery connected to the line through impedance-coils -0/ b', which is the usual practice in "common-battery work. These impedancecoils, while not objectionable, arel notneceslsary to the operation of my system, my improvement being adapted to any of the common-batterysystems m use, whethery .with or., without the impe?.` dance-coils. p

lI haveyshown three stations, (marked 1,'2, and 3 in the diagrammatic view, although, as before stated, 'any suitable number may be employed. From the subscribers termi-l nals 1,2192 'of the line-Wires a b may be traced ing-circuit d d d, including the bell d and the condenser di. In this ringing-circuit I include a circuit-breaking switch d3 for a purpose hereinafter described. From the same terminal a? b2 may be traced the talking-circuit e e, &c. "This talking-circuit includes a circuit-breaker e, normally closed, Operated by a relay f; also a circuit-breaker e2, normally opened, operated by the ordinary receiver-hook, a circuit-breaker e3, operated by a push-button d4, and a circuit-breaker et,

normally open, operated by a relay This circuit also includes the ltransmitter t and the receiver r in the usual way. From the terminal of the circuit-breaking switch e3 of the talking-circuit there is a branch line f f, which includes a relay f 2 and is connected to ground, as shown.' The relay f is included in the normally closedl circuit, which extends from the terminal b2,I through the circuit-breaker e4 and,line g y to ground. vThe terminal b2 rep-l resents-the 'same side of the line a, bthat is grounded at 'the central station, and hence no current will pass through this relay under ordinary conditions, as both ends ofthe wire are grounded on the same side, of thebattery B.

From a point preferably between the condenser d2 and bell d I extend a-branch line lt to a circuit-closing switch 7L", also adapted to be operated by the push-button d4 for a pur- 'pose hereinafter specified.

As thus described the operation of the device is as follows: The relay f., being in a normally grounded circuit andwithout current,` lalloiw'fs the circuit-breaker e to remain normally closed inthe talking-circuit e,

which is, however, open at the switch e2, Op-V erated by the telephone-hook. This talkingcircuit e isalso brokenat the, circuit-breaker e4, so'that these instruments are notvbridged across the line, and no current flows from one side of the line 'to the other until the switches e2 .andfe4 are both operated. The relay f bein in the grounded circuit and on the same si e of the line as e'and there being no current flowing'from one side of the line to the other, will not'be Operated. As soon as a bridge is established across the main linev'wires w bfhowever, the -current fiowing throughthis bridge will escape at all the legs at each subscriberfs station the usual ring-rk -or branches which are attached tothe line b.

' 3 5 circuit 'e e and byrneans ofthe switch h esta This bridge is established at any subscribers station uibhen the receiver is taken oft' the hook. The connection is first formed at c2, which establishes a circuit from line e through the branch e and the relay f2 to .ground This operates the relay f2 and closes the switch et, thus completing the bridge across the line. The operation of the .switch e4 also breaks the circuit through the relay f/ at the io subscribers station which has thus been operated and prevents the relay f from operating. In every other subscribers station, however,` the brid e having been thus established across the line, the current flows from4 i 5 the line-Wire a, through the subscribers talkingcircuit (Whose telephone has been removed .from thehook) to line-Wire b, and thence from line-wire b, to thenother subscribersA stations 'and to ground lthrough 'the relay f. zo The relays f/ are thus operated and the subscribers talking-circuit at every other station except the one first operated is broken and remains broken so long as current is flowing from one sidel of the line to the other z 5 through thebridg'e thus established.

Should a subscriber desire to communicate with another subscriber on the same line, having called that subscriber in the usual Way, if a simple calling-sign al is used, or having had 3o the operator at central call him if a selective signal is used, the subscriber presses the button d4 With his receiver oif the hook. This o erates. the circuit-breaker e3, which breaks t e bridge across thel-ine from the talkinglishes another bridge or circuit through the branch d and condenser d2 across the line between the terminals a2 b2. The condenser d? revente the battery-current from flowing,

4o ut Willv permit the alternating currents formed by the transmitters of the operator or the other subscriber to pass through, and thus enable the first subscriber to hear when thev connection has been made. After the proper connection has been "ablished be tweenl the called subscriber and the calling subscriber on the same line the calling subscriber releases his button d4 and the con-I l nection vis 'established between the two sub- 5o scribers. As soon as the called subscriber has removedhis telephone from' the hook a newl bridge will be established, which Will imme- .diately operate the relaysf in each of the other subscribers stations and lock them out except the two subscribers which have thus been connected.

- It Will be seen that by this construction an absolutely positive and automatic lock-out device is secured which can be attached to any 6o common-battery system. `The relays f and f2, with their circuit-breaking devices, are connected onto the line in the manner shown, but are normally inactive, the one because it is connected to the side of the line which is 6 5 grounded at central station and the other because it is in an open grounded circuit,

which Will only be closed by removing the telephone from the hook.

' The means provided for establishing connection between two subscribersou the saine line is such that the current is prevented from flowing across the bridge until 4the second subscriber called `has been connected, and hence prevents the .operation of the lock-out device until the calle-:l subscriber has come 'into the line, Which being accomplished all the other subscribers will. be immediately locked outu y Having thus described my invention, I claim- 1. In a common-battery telephone system, a main line having a series of talking instruments or subscribers stations'ada'pted to be bridged across the line, a relay in a normally 'open grounded line, a switch operated by the telephone-hook to close said grounded 'line through said relay, and a circuit-breaker operated by said' relay to close the talking-circuit across the telephone-line, a second relay at each subscriber's station in a normally grounded circuit from the opposite side of` the line, and having a circuit-breaker in the main talking-circuit, said second relay being adapted to. be operated whenever a bridge is established across the main line, substantially as specified.

2i In a common-battery party-line telephone systeni, a series of subscribers' 'stations, each having talking instruments adapt- -ed to be bridged across the line by a relay in a grounded circuit arb ted to be closed by the main telephone sWi ch or hook, a circuitcloser'op'erated by said relay to bridge the talking instruments across the line, a second relay on a grounded circuit from the opposite side of the line, and a circuit-breaker operated by the first relay to break the circuit through the second relay, substantially as and for the purpose specified.

3. In a common-battery party-line telephone system, ,a normally open grounded connection from one side vof said battery, a

Vgrounded connection at each subscribers station from the opposite side of said battery,

including a relay and the main telephoneswitch, a bridge across the line at each subscribers station including the talking instruments, and a circuit-closer operated by said relay, a second relay adapted 'to.operate a switch in said talking-circuit, said second relay being in a grounded circuit on the same side of' the battery as the ground at central station, and mean's'for breaking the circuit thrbugh said second relay when thefrst relay ist-operated, substantially as and for the purpose specified.

, 4. The combination With a central-energy' party-'line telephone system, having a batterv grounded at one side relays at each sub- -scribers station in grounded circuits extending from-opposite sides of said line, one'of said relays being normally closed to ground and the other relay being normally o ened at a switch operated 'by the main te ephonehook, the o eration of one of-said relays being adaptedp to close the talking-circuit across the line, and the operationlof the other relay being' adaptedfto break the talking-circuit across the line,' the closing-.relayc being also adapted to break the circuit from the relay in the same subscribers station When the same isoperated, substantially as and for the purpose specified. n

`5. In a central-energy party-line telephone system, a relay adapted to be thrown 1n circuit by the operation 'of the telephone-hook and to establish a connection across the line With the subscribers telephone instruments,

'means for breaking the connection in all'the ments across t eline and establish a connection through said talking instruments and the condenser, substantially as and for the purpose specified. l

In testimony whereof I have hereunto set my handthis 17th day of October, A. D.

WILLIAM M. BRUCE, JR.

Witnesses:

CHAs. I. WELCH,

F. LLEWELLYN WALKER. 

